1. Field of the Invention
The invention relates to an integrated circuit, a memory circuit, in particular a dynamic random access memory (DRAM) circuit, and to a method for operating an integrated circuit, in particular for driving a sense amplifier of the dynamic memory circuit.
2. Description of the Related Art
One requirement made of an integrated circuit, in particular DRAM memory components involves reducing the operating voltage ever further. As the operating voltage of a DRAM memory circuit decreases, the operating point of present-day conventional sense amplifiers is shifted toward ever lower voltages. At the same time, the threshold voltage of the transistors used therein correspondingly decreases, but the reverse current of the transistor rises exponentially as the threshold voltage decreases. Therefore, it is possible for the threshold voltage to be lowered only as far as a specific minimum value, in order to prevent the reverse current from rising above a maximum value. If the minimum value of the threshold voltage is reached, the operating conditions of the sense amplifier can no longer be set in a suitable manner upon further reduction of the supply voltage.
The operating points of the transistors of the sense amplifier have hitherto been realized either by a suitable choice of the threshold voltages of the transistors or by regulation of said threshold voltages such that the dynamic properties and at the same time the blocking behavior, too, have sufficed for operation of the memory circuit. However, this becomes more difficult as the supply voltages decrease further.
Furthermore, a decreasing operating voltage of a DRAM memory circuit has the effect of reducing the gain of the sense amplifier, with the result that the dynamic behavior of the memory circuit deteriorates.